In Priede U.S. Pat. No. 4,722,690, entitled Clock-spring Interconnector, an electrical interconnector member is provided, permitting electrical interconnection between, for example, an air bag assembly mounted on the steering column of a vehicle, and sensors mounted elsewhere in the vehicle. The sensors provide the electrical system with a signal that instantly activates the air bag in the event of a crash, causing the air bag to inflate to protect the car occupant.
Such an electrical interconnector member comprises an outer housing with a rotor member occupying an aperture in it in rotational relation thereto. First and second electrical connections are respectively placed on the outer housing and rotor, and connected by a coiled conducter which is loosely coiled around the rotor. By this means, the steering wheel may be rotated several turns in either direction without loss of electrical connection between members carried on the steering wheel such as the air bag assembly and the horn, and stationary members mounted elsewhere, such as the battery. Such a device is more reliable than an electrical brush and ring system, for example, which might fail, particularly during the impact of an accident.
As described in the Priede patent, it is important in mounting of the electrical interconnector member to be sure that the rotor is at a rotational center point relative to the housing as it is mounted onto the steering column. If the rotor is not centered, it may not be possible to turn the steering wheel of the car about its full range of travel from left to right without coming to an end of the ability of the interconnector to rotate without breaking the coil of the conductor. Thus, the interconnector must be installed on the steering column at a predetermined angular position, desirably its rotationally central position, so that the steering wheel may be rotated both to the left and the right in the full direction of travel. Typically, the interconnector may be capable of rotating two and one-half revolutions either clockwise or counterclockwise from the central position in which it is installed on the steering column while the wheels of the vehicle are straight.
The Priede patent discloses a breakaway member that prevents the rotor from rotating until it is mounted on the steering column. Thus, in the original manufacture of vehicles, the problem of orientation of the rotor relative to the housing is solved.
However, the problem of orientation of the rotor of an electrical interconnector of the coiled conductor type remains in the circumstance where repair work is done on the steering system and the interconnector is removed. There, the rotor may accidentally be rotated out of its rotationally central position. It is difficult to see from a quick inspection that such movement has taken place. Then, if such an interconnector is reinstalled onto the steering column, it may no longer coincide in its rotational capability with the complete range of rotational travel of the steering column. Thus, a small lack of adjustment of the interconnector when reinstalled may create major problems later on, when the finished vehicle is found to be incapable of its full range of steering, or upon attempt to steer the full range, the coiled conductor is broken, eliminating electrical interconnection with systems carried on the steering column.
In accordance with this invention, an electrical interconnector of the coiled conductor type is provided, in which the interconnector spontaneously locks when removed from its mounting on the steering column, or any other desired rotational member to which it is to be attached. Thus, the rotor can be expected to be rotationally immoveable until the time comes to reinstall it again on the steering column, at which time it becomes unlocked and capable once again of rotation.